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1.
对液体化工罐区静电产生的原因及可能产生的严重危害性做了详细的分析,并提出了防范措施.  相似文献   
2.
Protected areas are a cornerstone for forest protection, but they are not always effective during times of socioeconomic and institutional crises. The Carpathian Mountains in Eastern Europe are an ecologically outstanding region, with widespread seminatural and old‐growth forest. Since 1990, Carpathian countries (Czech Republic, Hungary, Poland, Romania, Slovakia, and Ukraine) have experienced economic hardship and institutional changes, including the breakdown of socialism, European Union accession, and a rapid expansion of protected areas. The question is how protected‐area effectiveness has varied during these times across the Carpathians given these changes. We analyzed a satellite‐based data set of forest disturbance (i.e., forest loss due to harvesting or natural disturbances) from 1985 to 2010 and used matching statistics and a fixed‐effects estimator to quantify the effect of protection on forest disturbance. Protected areas in the Czech Republic, Slovakia, and the Ukraine had significantly less deforestation inside protected areas than outside in some periods; the likelihood of disturbance was reduced by 1–5%. The effectiveness of protection increased over time in these countries, whereas the opposite was true in Romania. Older protected areas were most effective in Romania and Hungary, but newer protected areas were more effective in Czech Republic, and Poland. Strict protection (International Union for Conservation of Nature [IUCN] protection category Ia‐II) was not more effective than landscape‐level protection (IUCN III‐VI). We suggest that the strength of institutions, the differences in forest privatization, forest management, prior distribution of protected areas, and when countries joined the European Union may provide explanations for the strikingly heterogeneous effectiveness patterns among countries. Our results highlight how different the effects of protected areas can be at broad scales, indicating that the effectiveness of protected areas is transitory over time and space and suggesting that generalizations about the effectiveness of protected areas can be misleading.  相似文献   
3.
A method for quality screening is suggested to detect volatile impurities in inorganic coagulants that are used for drinking water treatment. Static headspace gas chromatography with mass spectrometry detection (HS–GCMS) is sensitive and selective to detect volatiles in low concentrations. This study has discovered that volatile organic impurities are detectable in ferric and aluminium-based coagulants which are used for drinking water treatment. For ferric chloride, 2-propanol was detected at a level of 17–24 μg ml−1, acetone at 0.7–1.7 μg ml−1, 1,1,1-trichloroacetone at 0.02–0.04 μg ml−1, trichloromethane at 0.01–0.02 μg ml−1 and toluene at 0.01–0.12 μg ml−1. For ferric chloride sulfate, acetone was detected at a level of 0.12 μg ml−1, 1,1,1-trichloroacetone at 0.06–0.08 μg ml−1, trichloromethane at 0.13–0.23 μg ml−1, bromodichloromethane at 0.04–0.06 μg ml−1 and dibromochloromethane at 0.04–0.05 μg ml−1. For aluminium hydroxide chloride, only trichloromethane was detectable, but below the method detection limits (MDL). Although the concentrations of these impurities in commercial coagulants are low, this observation is important and should have impact on water industries for them to pay attention to the chemicals they are using for drinking water production.  相似文献   
4.
In the present research, the effects of static magnetic field, with or without iron on the growth, the activity of certain enzymes (like polyphenol oxidase and phenyle alanine ammonialyase), the content of phenolic compounds and the essential oil composition of sweet basil (Ocimum basilicum) were studied. Treatment of plants with static magnetic field with or without iron led to decrease of the growth of plants as well as decrease in the activity of phenyle alanine ammonialyase and of phenolic compounds content. In addition in those plants exposed to magnetic field the amount of essential oils, notably of methyl chavicol, was increased. Exposure of plants to the magnetic field decreased the activity of polyphenol oxidase, whereas treatment of plants with iron when exposed to magnetic field increased polyphenol oxidase activity. In this group the content of essential oil was reduced.  相似文献   
5.
建立了顶空气相色谱法同时测定水中甲醛、乙醛、丙烯醛的方法。目标化合物连续测定9次的相对标准偏差分别为0.01,1.89,3.54;检出限分别为0.03μg/L,5.68μg/L,10.3μg/L,实际水样加标回收率在98%~101%。方法简便,快速,灵敏度高,基体干扰小。适用于地表水、地下水和工业废水中甲醛、乙醛、丙烯醛的同时、快速测定。  相似文献   
6.
根据蜂窝断面内循环三相生物流化床内混合液的连续性方程、动量方程和能量方程,利用Fluent软件对反应器内的流动状况进行了数值模拟.采用Fluent的前处理软件Gambit完成流化床的三维模型,利用Fluent主程序解析计算,并利用后处理软件实现计算结果的显示.模拟计算结果获得了反应器内静压力、静压差的变化规律,得到了液体循环速度、气含率沿纵向及横断面的分布.  相似文献   
7.
高压静电应用在饮食业油烟净化上的设计   总被引:2,自引:0,他引:2  
饮食业油烟排放时对大气产生较严重污染 ,本文介绍了高压静电在油烟净化上应用的原理和净化器的设计参数。  相似文献   
8.
通过对一台桥式电磁起重机静刚度和动刚度的理论计算,以及对其主梁的探伤检查,分析了桥式起重机在特殊工况下的静刚度和动刚度,指出了在设计时应考虑的安全性问题。  相似文献   
9.
根据一起电路事故,分析了静电与漏电的特性,提出了判别与排除设备静电与漏电的方法。  相似文献   
10.
静电喷漆工艺应用普及很快,但其生产过程的火灾危险性属甲类。其火灾危险主要在于使用的漆料或有机溶剂,喷漆作业中存在电火花、静电火花、高温热表面、自然发热等引火源。为防止火灾爆炸发生,要注重防火防爆安全管理和强化必要的安全技术措施。  相似文献   
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